JP7173937B2 - Charged particle beam device - Google Patents

Description

The present invention relates to a charged particle beam device.

Charged particle beam devices such as electron microscopes and ion microscopes are used to observe various samples with fine structures. For example, for the purpose of process control in the manufacturing process of semiconductor devices, scanning electron microscopes, which are one type of charged particle beam equipment, are used to measure the dimensions and defect inspections of semiconductor device patterns formed on semiconductor wafers, which are samples. applied to

One of the sample analysis methods using an electron microscope is to form a potential contrast image based on the secondary electrons obtained by irradiating the sample with an electron beam, and based on the analysis of the potential contrast image, Techniques for evaluating the electrical resistance of formed elements are known.

For example, Patent Literature 1 discloses a method of determining a defect by calculating an electrical resistance value from a potential contrast. Patent Document 2 discloses a method of predicting defect characteristics such as electrical resistance by creating a netlist describing information including electrical characteristics and connection information of circuit elements from potential contrast as an equivalent circuit. ing.

Japanese Patent Application Laid-Open No. 2003-100823 JP 2008-130582 A

2. Description of the Related Art In inspection and measurement of semiconductor devices, it is required to detect defects in the electrical characteristics of the device during the manufacturing process. However, with the technology disclosed in the patent document, it is difficult to estimate electrical characteristics in consideration of interactions between multiple devices using design data and test measurement data. In addition, there is a problem that data conversion for design data is troublesome and it takes a long time to estimate electrical characteristics.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a charged particle beam apparatus capable of estimating electrical characteristics in a short period of time in consideration of interactions among a plurality of devices.

A brief outline of typical inventions disclosed in the present application is as follows.

A charged particle beam apparatus according to a representative embodiment of the present invention includes a calculation device model for estimating a circuit of a sample, a database storing optical conditions of a charged particle beam irradiated to the sample, and a A charged particle beam optical system that controls a charged particle beam that irradiates a sample, a detector that detects secondary electrons emitted from the sample by irradiation with the charged particle beam and outputs a detection signal based on the secondary electrons, and a calculation generating a netlist for operation based on the device model for operation, estimating a first irradiation result when the sample is irradiated with the charged particle beam based on the netlist for operation and the optical conditions, and obtaining the first irradiation result and the optical conditions and a computing unit that compares the second irradiation result when the sample is irradiated with the charged particle beam based on the above.

Among the inventions disclosed in the present application, the effects obtained by representative ones are briefly described below.

That is, according to the representative embodiment of the present invention, it is possible to estimate the electrical characteristics in a short period of time while taking into consideration the interaction between multiple devices.

BRIEF DESCRIPTION OF THE DRAWINGS It is the schematic which shows an example of a structure of the charged particle beam apparatus which concerns on Embodiment 1 of this invention. 1 is a block diagram showing an example of the configuration of a charged particle beam device according to Embodiment 1 of the present invention; FIG. FIG. 3 is a diagram illustrating a calculation device model stored in a database; FIG. FIG. 4 is a diagram illustrating optical conditions stored in a database; FIG. 4 is a flow chart showing an example of a method of estimating a circuit for a sample; FIG. 10 is a diagram showing an example of a selection screen for a calculation device model; It is a figure which shows an example of the selection screen of optical conditions. It is a figure which shows an example of the result display screen after circuit estimation. FIG. 10 is a diagram showing another example of a result display screen after circuit estimation;

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings. Each embodiment described below is an example for realizing the present invention, and does not limit the technical scope of the present invention. In the embodiments, members having the same functions are denoted by the same reference numerals, and repeated description thereof will be omitted unless particularly necessary.

(Embodiment 1)
<Configuration of charged particle beam device>
FIG. 1 is a schematic diagram showing an example of the configuration of a charged particle beam device according to Embodiment 1 of the present invention. FIG. 2 is a block diagram showing an example of the configuration of the charged particle beam device according to Embodiment 1 of the present invention. As shown in FIGS. 1 and 2 , the charged particle beam device 1 includes a charged particle beam device body 10 , a computer 30 and an input/output device 50 .

<Main body of charged particle beam device>
The charged particle beam apparatus main body 10 has a configuration in which a lens barrel 10A is placed in a sample chamber 10B in which a sample 23 for inspection is accommodated, and a controller 11 is arranged outside the lens barrel 10A and the sample chamber 10B. ing. The lens barrel 10A includes an electron source (charged particle source) 12 for emitting an electron beam (charged particle beam), a pulse electron generator 19 for pulsing the electron beam, and adjusting the irradiation current of the irradiated electron beam. A diaphragm 13, a deflector 14 for controlling the irradiation direction of the electron beam, an objective lens 18 for condensing the electron beam, and the like are accommodated. Although not shown, the lens barrel 10A is provided with a condenser lens. If the electron beam is not pulsed, the pulse electron generator 19 may be omitted.

Further, the lens barrel 10A accommodates a detector 25 and the like that detect secondary electrons emitted from the sample 23 by irradiation with the electron beam and output a detection signal based on the secondary electrons. The detection signal is used for generation of SEM (Scanning Electron Microscopy) images, measurement of the size of the sample 23, measurement of electrical properties, and the like.

A stage 21, a sample 23, and the like are accommodated in the sample chamber 10B. A sample 23 is placed on the stage 21 . The sample 23 is, for example, a semiconductor wafer including a plurality of semiconductor devices, individual semiconductor devices, or the like. The stage 21 is provided with a stage driving mechanism (not shown), and can be moved within the sample chamber 10B under the control of the control section 11 .

The control unit 11 is a functional block that controls components of the charged particle beam device main body 10 . The control unit 11 controls operations of the electron source 12, the pulse electron generator 19, the diaphragm 13, the deflector 14, the objective lens 18, etc., based on the optical conditions and the like input from the computer 30, for example. Thus, the controller 11, the electron source 12, the pulsed electron generator 19, the diaphragm 13, the deflector 14, the objective lens 18, etc. constitute the charged particle beam optical system BS for controlling the electron beam.

Further, the control unit 11 moves the sample 23 to a predetermined position by controlling the stage driving mechanism based on, for example, optical conditions input from the computer 30 . Further, the control unit 11 controls the secondary electron detection process by the detector 25 by controlling power supply, control signal supply, and the like to the detector 25 .

The control unit 11 is implemented by a program executed by a processor such as a CPU, for example. Further, the control unit 11 may be configured by, for example, an FPGA (Field-Programmable Gate Array), an ASIC (Application Specific Integrated Circuit), or the like.

<calculator>
The computer 30 includes a computing unit 31 and a storage device 41, as shown in FIG. The calculator 31 is a functional block that estimates the circuit (or equivalent circuit) of the sample 23 . The computing unit 31 has, for example, a computing net list generator 32, an electron beam irradiation result estimation computing unit 33, and a comparator 34, as shown in FIG. The calculation netlist generator 32 generates a calculation netlist corresponding to the sample 23 based on a calculation device model and optical conditions, which will be described later. The calculation netlist generation unit 32 also updates the calculation netlist based on the comparison result of the comparator 34 .

The electron beam irradiation result estimation calculator 33 estimates the electron beam irradiation result based on the calculation netlist generated by the calculation netlist generator 32 . The comparator 34 compares the electron beam irradiation result (first irradiation result) estimated by the electron beam irradiation result estimation calculator 33 with the actually measured electron beam irradiation result (second irradiation result). .

In addition to these processes, the computing unit 31 is involved in displaying the estimated electron beam irradiation result, the measured electron beam irradiation result, and the netlist identified for the sample 23 (hereinafter also referred to as "estimated netlist"). processing, generation of an inspection image (SEM image or the like) of the sample 23 based on the detection signal, measurement of the size of the sample 23, measurement of electrical characteristics of the sample 23, and the like.

Like the control unit 11, the computing unit 31 may be implemented by a program executed by a processor such as a CPU, or may be configured by FPGA, ASIC, or the like.

The storage device 41 includes a database 42 , an optical condition storage section 43 , a calculation netlist storage section 44 , an electron beam irradiation result storage section 45 and an estimated irradiation result storage section 46 . The database 42 stores calculation device models (for example, DM1, DM2) and optical conditions (for example, LC1, LC2) used to generate a calculation netlist. Note that the calculation device model includes a model indicating defects in the device including the sample.

These calculation device models and optical conditions may be registered by the user by operating the input/output device 50, or by connecting the computer 30 to an external device and receiving the calculation device model from the external device. It may be done by The database 42 stores the device model for calculation and optical conditions as, for example, a LUT (Look Up Table).

FIG. 3 is a diagram illustrating a calculation device model stored in a database. A unique ID 42a (for example, DM1, DM2) is assigned to each computing device model, and each computing device model is identified by the ID 42a. Each calculation device model includes, for example, information such as model 42b, formula 42c, parameter type 42d, parameter value 42e, and other data 42f. Note that each computing device model may define only part of the information.

The model 42b is information that defines the circuit of the device. For example, information defining a circuit such as an RC parallel circuit is registered as a model 42b. Also, a device waveform model or the like may be registered as the model 42b. Equation 42c contains information that defines the electrical properties of the device that cannot be represented by a circuit. The parameter type 42d is information that defines the type of circuit elements included in the device, such as resistance (R) and capacitance (C). The parameter value 42e corresponds to each element of the parameter type 42d, and is information that defines the value of the circuit element corresponding to the parameter type 42d. For example, if resistance (R) and capacitance (C) are registered as parameter types, the corresponding parameter values are resistance and capacitance. The other data 42f includes, for example, information such as the shape of the device and physical properties of the device.

FIG. 4 is a diagram illustrating optical conditions stored in a database. A unique ID 42g (for example, LC1, LC2) is attached to each optical condition, and each optical condition is identified by the ID 42g. Each optical condition includes, for example, information such as irradiation energy 42h, irradiation current 42i, scan condition 42j, parameter value 42k, and other data 42l. Note that each optical condition may define only part of the information among them.

The irradiation energy 42h is information that defines the energy of the charged electron beam with which the sample is irradiated. The irradiation energy includes, for example, electron acceleration voltage, retarding voltage, and the like. Here, the term "retarding voltage" refers to a voltage applied to the sample to decelerate the electron beam (charged particle beam) immediately before the sample. The irradiation current 42i is information that defines the current of the electron beam. Note that the irradiation current is sometimes called a probe current.

The scan condition 42j is information that defines an electron beam irradiation method. The scanning condition 42j includes information such as scanning speed (scanning speed), scanning interval, and the like. The parameter value 42k is information that defines parameters related to electron beam irradiation. The parameter value 42k includes information such as magnification, opening angle, working distance, and the like. The other data 42l includes information other than these regarding optical conditions. The other data 42l may also store electron beam pulsing conditions (modulation conditions).

The electron beam pulsing conditions include, for example, pulse width, duty ratio, frequency, arbitrary patterns in which the pulse width and duty ratio change with time, and the like.

Note that the optical conditions are sometimes called electro-optical conditions or the like.

The optical condition storage unit 43 stores the selected optical conditions of the electron beam. The calculation netlist storage unit 44 stores the calculation netlist generated or updated by the calculation netlist generation unit 32 . The electron beam irradiation result storage unit 45 stores the actually measured electron beam irradiation result for the sample 23 based on the detection signal output from the detector 25 . The electron beam irradiation result stored in the electron beam irradiation result storage unit 45 may be a detection signal output from the detector 25, or may be an SEM image or the like based on the detection signal. The estimated irradiation result storage unit 46 stores the electron beam irradiation result for the sample 23 estimated by the electron beam irradiation result estimation calculator 33 .

The storage device 41 is composed of, for example, a non-volatile memory such as a flash memory. Moreover, a part of each storage unit included in the storage device 41 may be composed of a volatile memory such as a DRAM (Dynamic Random Access Memory) or an SRAM (Static Random Access Memory). Each storage unit included in the storage device 41 may be provided as a separate device, or may have a configuration in which each storage area is provided in one storage device.

<Input/output device>
The input/output device 50 is a functional block for operating the charged particle beam device 1, selecting a device model for calculation and optical conditions, and displaying the electron beam irradiation result for the sample 23, the estimated irradiation result, and the estimated netlist. The input/output device 50 includes, for example, a touch panel type display 60 . The display 60 includes, for example, an operation panel of the charged particle beam device 1, a selection unit 51 for selecting a calculation device model and optical conditions, an estimated netlist 52, an estimated irradiation result 53, an electron beam irradiation result 54, and the like. Is displayed.

<Circuit Estimation Method for Sample>
Next, a circuit estimation method for sample 23 will be described. In this embodiment, by comparing the electron beam irradiation result estimated using the calculation netlist generated from the calculation device model and the optical conditions with the actual electron beam irradiation result based on the optical conditions, the sample netlist estimation is performed. FIG. 5 is a flow diagram showing an example of a circuit estimation method for a sample. In the example of FIG. 5, steps S10 to S130 perform circuit estimation for the sample.

When the circuit estimation process is started, a calculation device model is selected (step S10). FIG. 6 is a diagram showing an example of a calculation device model selection screen. A calculation device model selection screen 61 in FIG. 6 shows, for example, a list 61a of calculation device models registered in the database 42 and a selection decision button 61e. The list 61a shows an ID display column 61b of registered calculation device models, a selection column 61c of calculation device models, and a detail display column 61d of each calculation device model.

The user selects a calculation device model having a circuit identical or similar to that of the sample 23 to be measured from a calculation device model selection screen 61 displayed on the display 60 . In this embodiment, one device model for calculation is selected. Specifically, the user checks the check box of the calculation device model to be selected, and then touches the selection determination button 61e to complete the selection of the calculation device model. FIG. 6 shows the case where the calculation device model with ID DM1 is selected. The selected calculation device model is sent to the calculation netlist generator 32 in FIG.

In step S20, the calculation netlist generation unit 32 generates a calculation netlist based on the calculation device model selected by the user. For example, the calculation net list generator 32 combines one of the model 42b, parameter type 42d, device shape, device physical property, etc. included in the selected calculation device model with the parameter value 42e to create a calculation net. The method of generating the computational netlist for generating the list is not limited to this.

In step S30, optical conditions are selected. FIG. 7 is a diagram showing an example of an optical condition selection screen. The optical condition selection screen 62 in FIG. 7 shows, for example, a list 62a of optical conditions registered in the database 42 and a selection decision button 62e. The list 62a shows an ID display field 62b for registered optical conditions, a selection field 62c for optical conditions, and a detail display field 62d for each optical condition.

The user selects arbitrary optical conditions from an optical condition selection screen 62 displayed on the display 60 . Specifically, the user checks the check boxes of the optical conditions to be selected, and then touches the selection decision button 62e, thereby completing the selection of the optical conditions. FIG. 7 shows a case where an optical condition with an ID of LC2 is selected. The selected optical conditions are stored in the optical condition storage section 43 in FIG.

In step S10, when the selection decision button 61e is touched and the selection of the calculation device model is completed, the calculation device model selection screen 61 may be erased and the optical condition selection screen 62 may be displayed. Further, when the selection of the calculation device model is completed, the optical condition selection screen 62 may be displayed superimposed on the calculation device model selection screen 61 . A button for redisplaying the calculation device model selection screen 61 may be provided on the optical condition selection screen 62 .

In setting the optical conditions, electron beam pulsing conditions (modulation conditions) are also used as necessary. The electron beam pulsing conditions may be used together with the optical conditions, or the electron beam pulsing conditions alone may be set as the optical conditions.

In step S40, the sample 23 is irradiated with an electron beam under the optical conditions selected in step S30. The optical conditions stored in the optical condition storage unit 43 are transmitted to the control unit 11 of the charged particle beam device main body 10 . Based on the received optical conditions, the control unit 11 controls each unit constituting the charged particle beam optical system BS to irradiate the sample 23 with the electron beam. When irradiated with the electron beam, secondary electrons are emitted from the sample 23 . When detecting the secondary electrons emitted from the sample 23, the detector 25 outputs a predetermined detection signal corresponding to the number of secondary electrons, irradiation energy, etc. to the computer 30 (computer 31).

In step S50, the actual electron beam irradiation result for the sample 23 is stored. The calculator 31 may store, for example, the detection signal (signal waveform) output from the detector 25 in the electron beam irradiation result storage unit 45 as the electron beam irradiation result. Further, the calculator 31 may generate an inspection image (such as an SEM image) based on the detection signal, and store the inspection image in the electron beam irradiation result storage unit 45 as the electron beam irradiation result. Further, the computing unit 31 may measure the charge amount of the sample 23 based on the detection signal and store the measured charge amount in the electron beam irradiation result storage unit 45 . Further, the calculator 31 may detect the brightness of the inspection image or the brightness of each pixel and store the detected brightness in the electron beam irradiation result storage section 45 .

At step S60, the calculation netlist generated at step S20 is stored in the calculation netlist storage unit 44. FIG. Although step S20 and step S60 are distinguished in FIG. 5, the process of step S60 may be performed in step S20.

In step S70, the electron beam irradiation result is estimated. The electron beam irradiation result estimation calculator 33 estimates the electron beam irradiation result for the sample 23 based on the calculation netlist stored in the calculation netlist storage unit 44 and the optical conditions stored in the optical condition storage unit 43. I do. The items of the electron beam irradiation result estimated here correspond to the measurement items of step S50. brightness, brightness of each pixel in the inspection image, and the like.

In step S<b>80 , the electron beam irradiation result estimated in step S<b>70 is stored in the estimated irradiation result storage unit 46 .

In step S90, the actual electron beam irradiation result and the estimated electron beam irradiation result are compared. The comparator 34 compares the actual electron beam irradiation result and the estimated electron beam irradiation result for each electron beam irradiation result item. The comparator 34 compares detection signals, for example, for each electron beam irradiation region or for each pixel of a detection image. Also, the comparator 34 compares, for example, the charge amount, the inspection image, the brightness of the inspection image, the brightness of each pixel in the inspection image, and the like. The comparator 34, for example, digitizes these irradiation results and calculates the magnitude of the difference between the actual electron beam irradiation result and the estimated electron beam irradiation result for each item to generate a comparison result. The comparator 34 may compare all of these items, or may compare only some of the items.

In step S100, it is determined whether or not the actual electron beam irradiation result and the estimated electron beam irradiation result match based on the comparison result calculated in step S90. For example, if the value of the comparison result is "0", the comparator 34 determines that these irradiation results match. On the other hand, if the value of the comparison result is not "0", the comparator 34 determines that these comparison results do not match. However, in practice, these irradiation results rarely match perfectly, so it is necessary to consider measurement errors within a predetermined range.

Therefore, the comparator 34 may determine that these irradiation results match if the value of the comparison result is equal to or less than a predetermined threshold value. A predetermined threshold is set for each item. When comparing a plurality of items, the comparator 34 may determine that these irradiation results match only when the comparison results for all the compared items are equal to or less than the threshold value. If the comparison result for the item is equal to or less than the threshold, it may be determined that these irradiation results match.

In step S100, when the comparator 34 determines that these electron beam irradiation results do not match (No), the process of step S110 is performed.

In step S110, the calculation netlist is updated. The comparator 34 , for example, transmits the comparison result to the calculation netlist generator 32 , and the calculation netlist is updated in the calculation netlist generator 32 . For example, based on the comparison result, the calculation netlist generator 32 changes the parameter values used to generate the previous calculation netlist, and uses the changed parameter values to generate the calculation netlist. In this manner, the calculation netlist generator 32 updates the calculation netlist. At that time, the calculation netlist generation unit 32 may change the parameter values based on the comparison results of a plurality of items. Alternatively, the calculation netlist generation unit 32 may preset parameters whose parameter values are changeable, and update the calculation netlist while changing the parameter values of only the changeable parameters.

The updated calculation netlist is stored in the calculation netlist storage unit 44 (step S60). Using the updated calculation netlist and optical conditions, the electron beam irradiation result is estimated again (step S70), and the estimated electron beam irradiation result is stored in the estimated irradiation result storage unit 46 (step S80). ). Then, the electron beam irradiation result estimated using the updated calculation netlist and the actual electron beam irradiation result are compared again (step S90).

The processing of steps S60 to S110 is repeatedly executed until the estimated electron beam irradiation result matches the actual electron beam irradiation result. Note that the calculation netlist may be updated in the calculation netlist storage unit 44 . In this case, the processes of steps S70 to S110 are repeatedly executed until the estimated electron beam irradiation result and the actual electron beam irradiation result match.

On the other hand, in step S100, when the comparator 34 determines that these electron beam irradiation results match (Yes), the process of step S120 is performed. In step S120, the calculator 31 (comparator 34) determines that the calculation netlist stored in the calculation netlist storage unit 44 can be identified as a netlist describing the circuit of the sample 23, This calculation netlist is stored in the estimated netlist storage unit 47 as an estimated netlist. In addition to the estimated netlist, the estimated netlist storage unit 47 may also store a correspondence table that associates the positions of the plug electrodes in the inspection image with each node of the estimated netlist.

In step S130, the estimation result and the measurement result are output to the input/output device 50. FIG. For example, the estimated netlist stored in the estimated netlist storage unit 47, the estimated electron beam irradiation result stored in the estimated irradiation result storage unit 46, and the actual electron beam stored in the electron beam irradiation result storage unit 45 The irradiation result is output to the input/output device 50 and displayed on the display 60 .

FIG. 8 is a diagram showing an example of a result display screen after circuit estimation. FIG. 8 shows, as a result display screen 70, a calculation device model designation section 71, an estimation result display section 72, an estimated electron beam irradiation result display section 73, and an electron beam irradiation result display section 74. FIG.

The content of the selected calculation device model, the selected optical conditions, and the like are indicated in the calculation device model designation section 71 . For example, the user can confirm the contents of the selected calculation device model and optical conditions by touching the calculation device model specifying section 71 . The estimation result display section 72 displays each parameter value used to generate the estimated netlist. In addition to the parameter values, the estimation result display section 72 may display information as to whether or not the parameters are changeable.

The estimated electron beam irradiation result display section 73 displays the estimated electron beam irradiation result. The estimated electron beam irradiation result display section 73 shows a graph in which the horizontal axis indicates the electron beam irradiation conditions (optical conditions) and the vertical axis indicates the lightness (brightness). Specifically, the estimated electron beam irradiation result display section 73 displays the electron beam irradiation results estimated for a plurality of nodes (plug electrodes). The estimated electron beam irradiation result display section 73 may display not only the estimation result using the estimated netlist but also the estimation result using the calculation netlist before being identified.

The electron beam irradiation result display section 74 displays the actually measured electron beam irradiation result. The electron beam irradiation result display section 74 also shows a graph in which the horizontal axis indicates the electron beam irradiation conditions and the vertical axis indicates the lightness (brightness). The electron beam irradiation result display section 74 displays electron beam irradiation results for a plurality of nodes.

The graphs of the estimated electron beam irradiation result display section 73 and the electron beam irradiation result display section 74 can be arbitrarily set. For example, a graph with the vertical axis representing the amount of secondary electrons detected may be shown. Further, the estimated electron beam irradiation result display section 73 and the electron beam irradiation result display section 74 may each display the waveform of the detection signal, the inspection image, and the like.

Further, the estimated electron beam irradiation result display section 73 and the electron beam irradiation result display section 74 may be combined to display the estimation result and the measurement result in a superimposed manner.

FIG. 9 is a diagram showing another example of the result display screen after circuit estimation. For example, images shown in FIG. 9 may be displayed on the result display screen 70 in addition to the images shown in FIG. FIG. 9A is an image obtained by inserting the coordinates of the plug electrodes into the inspection image. FIG. 9B is an estimated netlist. FIG. 9C is a correspondence table that associates the positions of the plug electrodes in the inspection image with each node of the estimated netlist. Also, a circuit diagram based on the estimated netlist may be displayed on the result display screen 70 .

In FIG. 5, the processes of generating a calculation netlist, measuring by electron beam irradiation, estimating the electron beam irradiation result, and the like have been described in order, but these processes may be performed in parallel. For example, the measurement by electron beam irradiation may be performed while generating the calculation netlist and estimating the electron beam irradiation result.

AI (Artificial Intelligence) based on techniques such as machine learning and deep learning may be used for processing such as the estimation of the electron beam irradiation result in step S70 and the updating of the calculation net list in step S110.

<Main effects of the present embodiment>
According to this embodiment, a calculation netlist is generated based on the calculation device model, and the electron beam irradiation result when the sample is irradiated with the electron beam is estimated based on the calculation netlist and the optical conditions. Also, the estimated electron beam irradiation result is compared with the electron beam irradiation result when the sample 23 is irradiated with the electron beam based on the optical conditions.

According to this configuration, it is not necessary to convert the external netlist input from the outside into the computational netlist, so it is possible to estimate the electrical characteristics of the sample 23 in a short period of time, thereby improving the throughput. becomes possible. In addition, it is possible to freely estimate the electrical characteristics and circuits of the sample 23 without being affected by the configuration of the external netlist, and it is possible to estimate the electrical characteristics in consideration of interactions between multiple devices.

Further, according to the present embodiment, when the estimated electron beam irradiation result differs from the actual electron beam irradiation result, the calculation device model is updated. Specifically, the calculator 31 updates the calculation netlist by changing the parameter values included in the calculation device model and creating the calculation netlist again using the changed parameter values. According to this configuration, it is possible to update the calculation netlist while suppressing the amount of calculation, and it is possible to suppress the load on the calculator 31 .

Further, according to the present embodiment, the electron beam irradiation result includes any one of the detection signal, the inspection image based on the detection signal, the brightness of the inspection image, and the brightness of each pixel in the inspection image. According to this configuration, it is possible to collate the irradiation result in various forms based on the detection signal.

Moreover, according to the present embodiment, the device model for calculation includes a model indicating defects of the sample 23 . According to this configuration, it is possible to easily detect defects (manufacturing defects) of the sample 23, and to improve the accuracy of circuit estimation.

Further, according to the present embodiment, the device model for calculation includes any one of a model that defines the circuit of the device, a mathematical formula that defines the electrical characteristics of the device, the shape of the device, and the physical properties of the device. According to this configuration, it is possible to estimate the circuit of the sample 23 from not only the circuit configuration but also the electrical characteristics, shape, physical properties, etc., and it is possible to improve the accuracy of circuit estimation.

Further, according to the present embodiment, the calculator 31 generates a correspondence table in which the position of the plug electrode in the inspection image and each node of the identified calculation netlist (estimated netlist) are associated with each other. According to this configuration, it becomes easy to grasp the correspondence between the netlist and the inspection image.

Further, according to the present embodiment, the electron beam irradiation result is estimated based on the optical conditions and the electron beam pulsing conditions. According to this configuration, it is possible to improve the accuracy of estimating the electrical properties of the sample 23 by the electron beam that changes intricately.

(Embodiment 2)
Next, Embodiment 2 will be described. In this embodiment, a plurality of calculation device models and one optical condition are used, and irradiation results are compared for each calculation device model. The configuration of the apparatus of this embodiment is the same as that of FIGS. 1 to 4, so description thereof is omitted.

<Circuit Estimation Method for Sample>
Next, a circuit estimation method according to this embodiment will be described. Also in the present embodiment, circuit estimation is performed along the flow of FIG. Processing different from that of the first embodiment will be mainly described below.

In step S10, a plurality of calculation device models are selected. For example, on the calculation device model selection screen 61 of FIG. 6, the user selects a plurality of calculation device models by checking the check boxes of the plurality of calculation device models and touching the select button 61e. be.

In step S20, a calculation netlist is generated for each of the plurality of selected calculation device models. Then, in step S60, each computational netlist generated in step S20 is stored in the computational netlist generator 32. FIG.

In step S70, the electron beam irradiation result is estimated using each computational netlist stored in the computational netlist generator 32. FIG. In step S<b>80 , the multiple electron beam irradiation results estimated in step S<b>70 are stored in the estimated irradiation result storage unit 46 .

In step S90, the actual electron beam irradiation result is compared with a plurality of estimated electron beam irradiation results. A comparator 34 generates a comparison result for each estimated electron beam irradiation result. In step S100, it is determined whether or not the actual electron beam irradiation result and each estimated electron beam irradiation result match.

If it is determined in step S100 that the actual electron beam irradiation result and all the estimated electron beam irradiation results do not match (No), all calculation netlists are updated in step S110. On the other hand, when it is determined that the actual electron beam irradiation result and one of the estimated electron beam irradiation results match (Yes), the process of step S120 is performed.

In step S<b>120 , the computational netlist corresponding to the estimated electron beam irradiation result that matches the actual electron beam irradiation result is identified as the netlist describing the sample 23 . The identified calculation netlist is stored in the estimated netlist storage unit 47 as an estimated netlist.

In step S<b>130 , estimation results for a plurality of calculation device models may be displayed on the result display screen 70 .

<Main effects of the present embodiment>
According to this embodiment, the following effects are obtained in addition to the effects of the above-described embodiments. According to the present embodiment, using a plurality of calculation device models and one optical condition, the estimated electron beam irradiation result and the actual electron beam irradiation result are compared for each calculation device model. . According to this configuration, it is possible to estimate the circuit and electrical characteristics of the sample 23 having a complicated configuration in a short time.

(Embodiment 3)
Next, Embodiment 3 will be described. In this embodiment, one device model for calculation and a plurality of optical conditions are used, and irradiation results are compared for each optical condition. Also in the present embodiment, the device configuration is the same as in FIGS. 1 to 4. FIG.

<Circuit Estimation Method for Sample>
Next, a circuit estimation method according to this embodiment will be described. Also in the present embodiment, circuit estimation is performed along the flow of FIG. Processing different from that of the first embodiment will be mainly described below.

In step S30, a plurality of optical conditions are selected. For example, on the optical condition selection screen 62 of FIG. 7, the user selects a plurality of optical conditions by checking the check boxes of the plurality of optical conditions and touching the select button 62e.

In step S40, the sample 23 is sequentially irradiated with the electron beam under a plurality of selected optical conditions. In step S50, the actual electron beam irradiation results for the sample 23 are stored in the electron beam irradiation result storage unit 45 for each optical condition.

In step S90, the actual electron beam irradiation result for each optical condition is compared with the estimated electron beam irradiation result. A comparator 34 generates a comparison result for each optical condition. In step S100, it is determined whether or not each electron beam irradiation result matches the estimated electron beam irradiation result.

If it is determined in step S100 that the plurality of electron beam irradiation results and the estimated electron beam irradiation result do not match (No), the calculation netlist is updated in step S110. On the other hand, when it is determined that one of the electron beam irradiation results matches one of the estimated electron beam irradiation results (Yes), the process of step S120 is performed.

In step S120, the computational netlist stored in the computational netlist storage unit 44 is stored in the estimated netlist storage unit 47 as an estimated netlist. At this time, the optical conditions when the actual electron beam irradiation result and the estimated electron beam irradiation result match may also be stored.

In step S<b>130 , measurement results for a plurality of optical conditions may be displayed on the result display screen 70 .

<Main effects of the present embodiment>
According to this lion mode, one device model for calculation and a plurality of optical conditions are used, and the estimated electron beam irradiation result and the actual electron beam irradiation result are compared for each optical condition. With this configuration, it is possible to improve the accuracy of estimating electrical characteristics.

[Modification]
It should be noted that this embodiment can also be applied to the estimated netlist identified in the first embodiment, for example, when it is executed under a plurality of optical conditions. In this case, steps such as selecting a device model for calculation, generating/updating a netlist for calculation, and identifying a netlist for calculation can be omitted as appropriate.

This facilitates the estimation of the electrical properties of the sample for which the netlist has been identified, making it possible to improve the estimation accuracy.

In addition, the present invention is not limited to the above-described embodiment, and includes various modifications. Also, part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of one embodiment. . Moreover, it is possible to add, delete, or replace a part of the configuration of each embodiment with another configuration. It should be noted that each member and relative size described in the drawings are simplified and idealized in order to explain the present invention in an easy-to-understand manner, and may have a more complicated shape in mounting.

DESCRIPTION OF SYMBOLS 1... Charged particle beam device, 10... Main body of charged particle beam device, 23... Sample, 25... Detector, 30... Calculator, 31... Computing unit, 41... Storage device, 42... Database, 50... Input/output device, 60... Display, BS... Charged particle beam optical system

Claims (11)

a database storing a calculation device model for estimating a circuit of a sample and an optical condition of a charged particle beam irradiated to the sample;
a charged particle beam optical system that controls the charged particle beam that irradiates the sample based on the optical conditions;
a detector that detects secondary electrons emitted from the sample by irradiation with the charged particle beam and outputs a detection signal based on the secondary electrons;
generating a calculation netlist based on the calculation device model, estimating a first irradiation result when the charged particle beam is applied to the sample based on the calculation netlist and the optical conditions; a computing unit that compares the first irradiation result with a second irradiation result when the charged particle beam is irradiated to the sample based on the optical conditions;
comprising
Charged particle beam device. In the charged particle beam device according to claim 1,
When the first irradiation result and the second irradiation result are different, the computing unit updates the device model for calculation so that the first irradiation result and the second irradiation result match. if the computational netlist is a netlist describing the circuit of the sample,
Charged particle beam device. In the charged particle beam device according to claim 2,
The calculator changes parameter values included in the calculation device model, and updates the calculation netlist using the changed parameter values.
Charged particle beam device. In the charged particle beam device according to claim 1,
The second irradiation result includes any of the detection signal, an inspection image based on the detection signal, the brightness of the inspection image, and the brightness of each pixel in the inspection image.
Charged particle beam device. In the charged particle beam device according to claim 1,
wherein the computational device model includes a model indicative of device defects;
Charged particle beam device. In the charged particle beam device according to claim 1,
The device model for calculation includes any one of a model that defines the circuit of the device, a mathematical formula that defines the electrical characteristics of the device, the shape of the device, and the physical properties of the device.
Charged particle beam device. In the charged particle beam device according to claim 6,
the computational device model includes parameter values of circuit elements included in the circuit of the device;
Charged particle beam device. In the charged particle beam device according to claim 2,
The computing unit generates an inspection image based on the detection signal, and generates a correspondence table that associates the position of the plug electrode in the inspection image with each node of the identified computing netlist.
Charged particle beam device. In the charged particle beam device according to claim 1,
The database stores pulsing conditions for the charged particle beam,
The charged particle beam optical system controls the charged particle beam that irradiates the sample based on the optical conditions and the pulsing conditions,
The computing unit estimates the first irradiation result based on the optical condition and the pulsing condition.
Charged particle beam device. In the charged particle beam device according to claim 1,
The calculator uses a plurality of the device models for calculation and one optical condition, and compares the first irradiation result and the second irradiation result for each of the device models for calculation.
Charged particle beam device. In the charged particle beam device according to claim 1,
The computing unit uses one of the device models for calculation and a plurality of the optical conditions, and compares the first irradiation result and the second irradiation result for each of the optical conditions.
Charged particle beam device.

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